Rule 608.2c explains that when resolving spells and abilities, it's possible for later text to modify the meaning of earlier text, the classic example being something like “Destroy target creature. It can’t be regenerated”, where trying to apply each sentence one by one in order would result in weird, nonsensical outcomes. In these cases, you instead need to apply the rules of English to make sense of the text as a whole. Copying a spell (or ability) and choosing new targets for it is one of these cases. Choosing new targets for the copy is not a separate action performed after the copy has been created–instead, it's part of the process of putting the copy onto the stack, and the copy is created with those new target(s) already in place.
As such,
Wild Defiance triggers a total of three times in this scenario: once for
Bear Cub upon the initial casting of
Jump, once for
Gray Ogre upon changing the target of the original Jump, and once for Bear Cub again upon the creation of a copy that targets it.
Once everything on the stack has resolved,
Bear Cub will be an 8/8 and
Gray Ogre will be a 5/5.